avatars, core files, and upgrades, oh my

Installation instructions for the latest Avatars plugin include:

options-discussion.php - goes in /wp-admin - overwrite existing file

Does this mean that file needs to be replaced upon each WPMU upgrade? Or will Avatars continue to work even when wp-admin files get overwritten next time WPMU is upgraded?

Just trying to prepare for headaches down the road since it seems like I've been upgrading things every couple weeks (or days) lately. Many thanks.